Benign thyroid teratomas manifest painful cystic and solid composite nodules: three case reports and a review of the literature

[Surgery for mediastinal teratoma containing pancreatic tissue]

Surgery for mediastinal tumors is still one of the most difficult in modern medicine. This is due to vital organs and various nature of tumors in this area. Teratomas are relatively rare among mediastinal tumors. However, they have certain features that is important for treatment strategy and management of possible complications. This can complicate diagnostic algorithm, exclude transthoracic biopsy and contribute to active surgical approach even for benign process. Oncogenesis of teratoma has its own characteristics. Tissues of different organs are always present in this tumor. Among these, pancreatic tissue inclusions are rare. A few data in the world literature on the treatment of such patients do not allow to develop a universally accepted algorithm of diagnosis and treatment. The authors present two patients with mediastinal teratoma. The second patient had teratoma with pancreatic tissue. The authors discuss the diagnostic algorithm for similar cases. A special attention is paid to description of possible complications throughout long-term follow-up period. Surgical aspects including the choice of access and local spread of process (adhesions in the area of surgical interest) are considered. The report on the treatment of two patients with rare mediastinal tumors containing pancreatic tissue will be useful for primary care physicians, thoracic surgeons, oncologists and morphologists.

Thyroid Teratoma in a Pediatric Patient

Congenital thyroid teratomas are rare in the pediatric population as well as in the adult population. While they are typically found in the gonadal regions, extragonadally, they are commonly found in the sacrococcygeal region, with teratomas of the head and neck rarely found, comprising only about 1%-6% of all pediatric teratomas. Due to a concern for potential airway compromise and increased risk of malignancy with age, early surgical excision is recommended. In this case report, we present a two-year-old female who underwent laryngoscopy with subsequent right thyroid lobectomy for a large thyroid mass, which was found to be a congenital thyroid teratoma.

Unusual findings in thyroid cytology and histology

INTRODUCTION

Although cytology and histopathology of thyroid lesions generally fall into common, well-defined categories, there are uncommon cases with unusual fine needle aspiration (FNA) findings or histology. Herein, we review the prevalence and characteristics of rare thyroid cytology and histopathology findings at a tertiary hospital.

METHODS

Institutional data from >31,000 patients with a thyroid pathology from 1995 to 2013 were queried. Both cytology and histology were available in 6,693 patients. After exclusion of the common cytological categories detailed by The Bethesda System for Reporting Thyroid Cytopathology (TBSRTC) and common histopathology categories, 90 patients with either an unusual FNA, histopathology, or both were identified.

RESULTS

A total of 90 cases were included (19: only unusual FNA; 25: only unusual histology; 46: both unusual cytology and histopathology). The positive predictive value of an unusual FNA for discovering an unusual lesion was 71% (95% CI: 58%-81%). The majority (66%) were females and median age was 59 years. On histopathology, 80 (88%) cases were malignant, 72 (90%) of which were initially diagnosed as malignant on FNA. Of the 10 benign lesions, 8 (80%) also had a benign FNA. Patients with unusual malignant lesions were significantly older than those with unusual benign lesions (62 vs. 44 years; P: 0.004).

CONCLUSION

Unusual cytopathological and histopathological findings in thyroid comprise a varied group of tumors that are individually rare but collectively common. A preoperative FNA with an unusual cytopathology is likely to lead to an unusual histopathological diagnosis; however, its diagnostic accuracy in differentiating benign from malignant is lower than the accuracy of cytopathology of conventional TBSRTC. Diagn. Cytopathol. 2017;45:185-190. © 2016 Wiley Periodicals, Inc.

Benign teratoma of the thyroid gland

Although pathology reports of thyroid tissue in ovarian teratomas are abundant, benign teratomas of the thyroid are extremely rare in adolescents and adults. Therefore, their clinical characteristics are still not well characterized. We report a case of a 54-year-old woman with a growing mass in her neck. Left lobectomy of the thyroid revealed it to be a benign thyroid teratoma composed of tissues from all three germ layers. Preoperative evaluations included thyroid ultrasonography (US), ultrasound-guided fine needle aspiration cytology (FNAC), and computed tomography (CT) of the neck. A 4.7-cm, well defined, predominantly hypoechoic mass intermingled with hyperechoic internal lesions, was observed in the inferior portion of the left thyroid lobe with substernal extension on US. The posterior extent of the nodule was not visualized due to deep attenuation of the echo. US-guided FNAC failed to reveal any thyroid follicular cells, but suggested a benign cystic tumor. Neck CT hinted at the diagnosis of teratoma because the mass contained large amounts of fat, and the margin was well defined. Extrathyroidal extension and cervical lymphadenopathy were not seen. She underwent left thyroid lobectomy, and histologic examination confirmed benign thyroid teratoma. To the best of our knowledge, this is the first case report of benign thyroid teratoma in Korea.